HMGBs bind to RB. (A)
In vitro HMGB:RB protein interaction. The GST capture assay was performed as described previously.13,15 wtHMGB1–4 wt proteins, but not HMGB1–3 mutLXCXE or HMGB4 mutLXCXD mutants, were pulled-down by 35S-methionine-labeled GST-wtRB proteins. The input lanes showed 10% of IVT wtHMGB1–4 or 10% of IVT HMGB1–3 mutLXCXEs or HMGB4 mutLXCXD products used in the assay. (B) Intracellular association of HMGBs and RB. HMGB1–4 were detected in RB IPs from nuclear extracts of MCF-7 and T-47D cells by WB. Representative results were shown from three independent experiments. Rb, retinoblastoma; WB, Western blot; IP, immunoprecipitation; GST, glutathione-S-transferase. LXCXE, leucine-X-cysteine-X-glutamic (X=any amino acid); LXCXD, leucine-X-cysteine-X-asparagine (X=any amino acid); wt, wild-type.